Caption: Coagulation factor complex molecule. Molecular model showing a blood clotting factor VIIa-tissue factor complex molecule. Tissue factor, also known as factor III, is found on the outside of blood vessels. When the vessel is injured it comes into contact with factor VII (FVII) circulating in the blood stream. They bind together, activating FVII as part of the coagulation cascade, the physiological process that leads to blood clotting in the case of injury.